As you can see the little rubber collar thingy should sit below the boot floor and is probably there to help prevent the hose being pulled off the main fuel line when the tank is moved to get at the damper bolts: -

Here's the pesky holes in question and it just seams that my fuel hose had gone brittle with age, plus I had disturbed it recently when I was checking the earth's and wiring to solve an indicator problem. I've checked the holes and the smaller one doesn't have a sharp edge, plus I've pulled and twisted the new hose whilst through it and it doesn't leave any marks or cuts so it should be fine for another 17 years.

Anyway Somerford Minis (who are superb) came to the rescue again and I received the new fuel hose and clips etc that I ordered from them within a day! I should have ordered a replacement vent pipe too because on closer inspection that's starting to split and break up too, so I'll have to give them a ring in the morning.
It would be nice to have a dummies guide to Mini repairs, but we're very lucky to have such helpful and very knowledgeable people here on TMF anyway. So thanks again and thanks for the photo's Anorak.
